Wide Area Control Research Articles

Designing the Next Generation of Real-Time Control, Communication, and Computations for Large Power Systems

The power grid is not only a network interconnecting generators and loads through a transmission and distribution system, but is overlaid with a communication and control system that enables economic and secure operation. This multilayered infrastructure has evolved over many decades utilizing new technologies as they have appeared. This evolution has been slow and incremental, as the operation of the power system consisting of vertically integrated utilities has, until recently, changed very little. The monitoring of the grid is still done by a hierarchical design with polling for data at scanning rates in seconds that reflects the conceptual design of the 1960s. This design was adequate for vertically integrated utilities with limited feedback and wide-area controls; however, the thesis of this paper is that the changing environment, in both policy and technology, requires a new look at the operation of the power grid and a complete redesign of the control, communication and computation infrastructure. We provide several example novel control and communication regimes for such a new infrastructure.

Use of Satellite Technologies for Power System Measurements, Command, and Control

This paper analyzes the use of wide-area measurement technologies including satellite-based methods for the command and control of power systems. The methods studied include the global positioning system (GPS) and low earth orbit satellites (LEOS). Satellite technologies have been used in a variety of applications requiring precise timing between geographically diverse locations. The deregulation of the electric power industry is placing increased demands on power transmission system utilization. Because deregulated power systems utilize long-distance high-power exchanges, satellite-based communication systems are useful in control of geographically large interconnected power systems. In this paper, the satellite-based measurements and commands are introduced for wide-area control. With the support of wide-area signals, a multiagent supervisory-level power system stabilizer is proposed here as a potential wide-area control structure. Increased loading of transmission facilities is an impetus for accurate dynamic thermal overhead electrical conductor ratings. The application of satellite-based measurement for improving the dynamic thermal rating of overhead transmission circuits is suggested.

AERIAL ULTRA-LOW–VOLUME ASSESSMENT OF ANVIL 10+10® AGAINST ANOPHELES QUADRIMACULATUS

Against caged field-collected adults of Anopheles quadrimaculatus, optimized aerial applications of ANVIL 10+10 at 18.4 ml (1.63 g active ingredient)/0.4 ha produced a mean mortality of 92% at 1, 12, and 24 h after treatment. These trials were conducted with 7 stacked passes applied 1,067 m upwind of the target site when wind velocity was 18-21 km/h at an application altitude of 46 m and 5-10 km/h at groundlevel. When the wind velocity aloft was greater than might be operationally acceptable (27 km/h), reduced efficacy (64% mortality) was observed in the bioassay site (1,524 m downwind from 11 stacked passes) in an unreplicated application. Droplets from the 2 tail-mounted Beecomist 360-A-12-V rotary atomizers (fitted with wire sleeve cages of size 40 mesh) collected on spinning Teflon-coated slides in the target area averaged a volume mean diameter (VMD) of 29 microm and a droplet density of 39 droplets/cm2 in 18- to 21-km/h winds. With 27-km/h winds aloft and a greater application offset, the VMD and droplet density dropped to 23 microm and 18 droplets/cm2, respectively. Coupled with unreplicated results from a nonoptimized application, these tests provide further documentation of the efficacy of ANVIL 10+10 for wide-area adult mosquito control and for optimization technology.

Wide area system monitoring and control

This article describes the transition from phasor-based wide area measurement to real time monitoring, control, and protection. The power system phenomena to deal with are reviewed, and key concepts in control and protection are addressed along with different design principles and architectures. Examples of analysis tools, monitoring tools and concepts for control and protection are given. The use of PMU improved the observability of the power system dynamics.

Power system stability agents using robust wide area control

Conventional power system stabilizers (PSSs) are major local damping controllers acting through generator excitation systems. There are studies that suggest that remote signals could increase damping beyond that attainable by local signals. In this paper, a supervisory level power system stabilizer (SPSS) using wide area measurements is proposed. The robustness of the proposed controller is capable of compensating for the nonlinear dynamic operation of power systems and uncertain disturbances. The coordination of the robust SPSSs and local PSSs is implemented based on the principles of multiagent system theory. This theory is an active branch of applications in distributed artificial intelligence (DAI). The performance of the robust controller as a power system stability agent is studied using a 29-machine 179-bus power system example.

Wide-area fuzzy logic control of voltage/VAr under simulated online conditions

This work describes the development of a fuzzy logic tool capable of controlling system voltages and VAr resources, as well as processing alarms related to voltage stability. The fuzzy controller monitors voltages and VAr resources and generates appropriate control signals to each VAr source to maintain acceptable system voltage levels. The fuzzy alarm processor generates an individual alarm for each voltage region, and a general alarm signal that indicates the overall system condition. A prototype fuzzy controller/processor has been interfaced with power system simulation software to test its performance under simulated on-line conditions.

96/01639 Lighting supplement

With deregulation and growth of the power industry, many power system elements such as generators, transmission lines, are driven to operate near their maximum capacity, especially those serving heavy load centres. Wide Area Controllers (WACs) using wide area or global signals can provide remote auxiliary control signals to local controllers such as automatic voltage regulators, power system stabilizers, etc. to damp out system oscillations. However, since the power system is highly nonlinear with fast changing dynamics, it is a challenging problem to design an online system monitor/estimator, which can provide dynamic intra-area and inter-area information such speed deviations of generators to an adaptive WAC continuously. This paper presents a new kind of recurrent neural networks, called the Echo State Network (ESN), for the online design of a Wide Area Monitor (WAM) for a multimachine power system. A single ESN is used to predict the speed deviations of four generators in two different areas. The performance of this ESN WAM is evaluated for small and large disturbances on the power system. Results for an ESN based WAM and a Time-Delayed Neural Network (TDNN)-based WAM are presented and compared. The advantages of the ESN WAM are that it learns the dynamics of the power system in a shorter training time with a higher accuracy and with considerably fewer weights to be adapted compared to the design-based on a TDNN.